Improved apparatus for inserting fusible plugs in steam-generators



PATEN FFICE,

JOSEPH FREN (1H, OF PITTSBURG, PENNSYLVANIA.

i IMPROVED APPARATUS FOP INSERTING FUSiBLE PLUGS IN STEAM-GENERATORS.

Specification forming part of Letters Patent No. 58,092, dated September 18, 1866.

To all whom t may concern:V

Be it known that 1, JOSEPH FRENCH, of Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Mode of Replacing Fusible Plugs in Flues, and I do hereby declare the following to be afull, clear, and exact description thereof, reference being had to the accompanying drawings, forming part of this specification, in which- Figure l is a section of a tubular boiler and an exterior view of my improved apparatus, excepting at the lower end, which is shown in section. Fig. 2 is a vertical section through t my apparatus and the boiler to which it is applied.

In both iigures the same letters of reference are used to denote similar parts.

It is a well-known device to insert a plug of fusible alloy in one of the flues of a steamboiler, the alloy being so composed of such ingredients and in such proportions as to melt whenever the temperature of the steam or water within the boiler becomes so great as to be unsafe, or whenever the water gets so low as to allow the fine to become overheated, the plug of alloy being placed in a hole in the flue, which, when the plug is removed, allows the water or steam from the interior of the boiler to enter the flue and extinguish the tires under the boiler. As it is necessary to replace they plug of alloy in the hole in the flue before the boilers can be filled above its level or steam raised therein, it is important to have a safe and convenient mode of inserting the plug without making any opening from without into the steam or water space of the boiler.

rlhis, then, is the object of my invention, which 1 shall proceed to describe:

In the drawings, (t is an ordinary cylindrical boiler, with two longitudinal ilues, b b', communicating with the furnace under the boiler in the ordinary manner. On the top of one of the iiues, b', is placed a metallic ring, c, which is screwed into a hole in the flue in such a manner that the cavity of the ring opens into the interior of the flue with its axis in a vertical position. The cavity or bore of the ring is circular, but smaller at bottom than at top, so as to form a coneseat for the plug of fusible alloy which is ininserted therein, as shown in Fig. 1. The

upper portion of the ring c is hemispherical in shape, or a section of a sphere, although this is not necessary, as a conical shape would answer the same purpose. Immediately above the ring c a cylindrical sleeve, d, is inserted through a hole in the boiler, through which sleeve is passed the tubular rod e, which extends into the boiler far enough for its lower end to rest upon the top of the ring c, the end of the tubular rod being of such shape as to fit closely upon the ring, so as to make a steamtight joint. The rod e also extends a convenient distance above the top of the boiler, and has a hand-wheel, Z, attached to its upper extremity. The diameter of the bore of the tubular rod e is equal to the larger .diameter of the ring c, and a little greater than the larger diameter of the fusible plug n. The upper end of the tubular rod c is closed by a screw, f. The lower end of t-he sleeve d is capped for a short distance, so as to form a female screw, and corresponding screwthreads t" project from the exterior of the tubular rod e, so that it may be screwed down tightly upon the ring c, as shown in Fig. 2.

That portion of the sleeve d which projects outside of the boiler is of smaller diameter than the lower part, which is within the boiler, and a follower-ring, g, placed around the sleeve d outside of the boiler, and a nut, h, screwed down around the upper part of the sleeve d, serve to keep it firmly in place and prevent the escape of steam. As a furtherI precaution to prevent the leakage of steam, a stuffing-box, 7c, is placed around the tubular rod e at the top of the sleeve d.

The operation of this apparatus is as follows When the fusible plug has been blown out ofthe ring c, and it is desired to insertanother one, the tubular rod is screwed down into the upper surface of the ring c. This prevents the further escape of steam into the flue b', and also into the rod e. tubular rod e is then removed, and a plug of fusible alloy is inserted into the rod from the top, and falls down into the cavity of the ring c, being prevented from passing through into the flue by its tapering'shape. The hole in the top of the flue being thus closed, the rod c is screwed up a short-distance to the position shown in Fig. 1, care being taken to replace the screw f in the top of the rod before-p the rod is raised, as otherwise the steam or The screwfou top of the hot Water from the boiler would rush up the bore of the rod e as soon as it was raised from the ring c. When the rod is in the position shown in Fig. 1, the steam or water has free access to the top of the plug` of alloy.

My improvement is applicable to locomotiveboilers as Well as to the ordinary description of steam-boilers constructed with iifues.

Having` thus described my improvement, what I claim as my invention, and desire t0 secure by Letters Patent, is-

The'combination of the ring c, for holding the fusible plug in the flue, the tubular rod c, and screw f, for closing the bore of the rod e, constructed and arranged substantially as and for the purposes hereinbefore described.

In testimony whereof the said JOSEPH FRENCH'hns hereunto set his hand.

JOSEPH FRENCH.

Witnesses:

W. D. LEWs, ALLAN C. BAKEWELL. 

